Implant anchor systems

Abstract

The present invention provides implant devices configured to become anchored within tissue so that they do not migrate despite experiencing aggressive migration forces applied by the highly dynamic movement of muscle tissue that surrounds them. Additionally, methods for placing the devices so that they remain securely anchored within the tissue are provided. The devices are comprised of a flexible body, preferably formed from a helical wound spring. In a preferred embodiment the spring is wound from a ribbon-like filament having series of barbs or ridges formed along the proximal facing edge of the wound ribbon. The ribbon-like filament may be etched from a flat sheet of material, having barbs formed along one edge. The filament may then be wrapped into a helical coil shape to take the form of an implant having barbs formed along the proximally facing edge of each coil to resist migration.

Description

FIELD OF THE INVENTION[0001]This invention relates to tissue implant devices and methods of their use. In particular, the devices and methods concern systems for anchoring the implants in tissue so that they do not migrate after implantation.BACKGROUND OF THE INVENTION[0002]There are a variety of applications for tissue implant devices in the human body. Such applications include electrical pacing leads or other tissue monitoring devices or tissue support structures such as endoluminal stents. A device implanted in tissue may experience migratory forces applied by movement of the surrounding tissue into which the device has been implanted. Migration is especially a problem in muscle tissue that regularly contracts and relaxes around the device. Because the device is static and is relatively inflexible, rather than absorbing the forces applied by the tissue, those forces act on the device to move it in the tissue. Migration of the device ultimately may lead to ejection of the device ...

AI Technical Summary

Benefits of technology

[0008]Generally, the spring implant devices may be considered to have a body having proximal and distal portions. In the present application, proximal is understood to mean the direction leading external to the patient and distal is understood to mean any direction leading internally to the patient. The implant devices discussed herein are delivered into the tissue in a distal direction so that the body is implanted within the tissue and the proximal end of the device is approximately flush with the tissue surface or slightly submerged under the surface. The configuration of the barbs resists migration of the device proximally back out of the tissue. Additionally, the barbs may serve to resist rotational movement of the device so that it does not “unscrew” out of the tissue.

[0009]In an embodiment of the invention, a flexible implant device formed from a helical spring body may be formed from a filament having a non-circular cross-section. For example, a filament having a rectangular cross-section may serve to prevent migration through the tissue in the axial direction by several mechanisms. When the helical coil is wound such that the major axis of the rectangular cross-section is substantially perpendicular to the longitudinal axis of the body of the device greater axial flexibility is imparted to the spring, while maintaining sufficient radial stiffness to resist crushing by the tissue, than would be possible with a round cross-sectional filament material. Increased axial flexibility of the device permits it to move with surrounding tissue, absorbing forces that would otherwise tend to push the device out of position in the tissue. Additionally, as surrounding tissue herniates through the individual coils of the device, the orientation of the major axis of the rectangular cross-section of the filament to be perpendicular to the longitudinal axis of the device presents a larger surface area engaging the tissue to resist axial migration.

[0010]Alternatively, the major axis of the rectangular cross-section filament may be oriented at an angle that is acute to the longitudinal axis of the device, so that the filament is canted in the proximal direction, to facilitate insertion of the device in the distal direction during implantation into the tissue. The canted orientation of the rectangular cross-sectional filament still provides the flexibility benefits of the perpendicular orientation discussed above and may enhance anchoring capability by presenting a leading proximal facing edge that serves to grip into tissue.

[0013]It is an object of the present invention to provide a tissue implant device that resists migration from the tissue into which it is implanted by offering improved anchoring capability.

[0014]It is another object of the present invention to provide a tissue implant device having an anchor mechanism that is easy to integrate into small mechanical devices.

[0015]It is yet another object of the present invention to provide an implant device that resists migration by its inherent flexibility and ability to absorb migratory forces exerted by surrounding tissue.

Problems solved by technology

Migration is especially a problem in muscle tissue that regularly contracts and relaxes around the device.

Migration of the device ultimately may lead to ejection of the device from the tissue.

An ejected device could prove harmful to a patient if it enters the blood stream and blocks blood flow to a critical organ such as the brain.

Conventional methods of anchoring a device to tissue such as by stapling or suturing prove difficult in applications where there is exaggerated and constant movement of the subject tissue because it is difficult to accurately apply a suture or staple to the intended location.

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